This invention relates to a motion picture camera using a film cassette and having a synchronous recording system which permits synchronous sound recording.
As is well known, there are two types of film cassettes, i.e., the cassette for a sound film and a cassette for a silent film. The former differs from the latter in its size such that the height of the former is 15 mm greater than that of the latter.
It is also well known that the film speed of the sound films can be either 18 frames per second or 24 frames per second. Thus, if sound cassettes are used at a film feed speed other than 18 or 24 frames per second, variations in the sound generating frequency result, thereby failing to achieve the intended normal regeneration of sound in synchronism with the motion picture.
On the other hand, however, while the normal film feed speed for a silent film is set to 18 frames per second, it sometimes happens that a different film feed speed is required. Consequently, a camera of this type is designed so as to permit switching of the film feed speeds, for instance from 18 frames per second to 54 frames per second or 12 frames per second.
This is also the case with such a motion picture camera having a synchronous sound recording system and using a film cassette as described. In other words, the camera may be loaded with either a silent film cassette or a sound film cassette, thus permitting either silent film photographing or sound film photographing coupled with synchronous sound recording. When a sound film cassette is loaded in a camera but the film feed speed is set to a film feed speed other than 18 or 24 frames per second, i.e., to 54 frames per second or 12 frames per second, however, then the camera fails to record the sound in proper synchronization with the photographing, thereby wasting the costly sound film.